A power converter system (power transfer system) is required to convert/transfer power from an input power source to an energy storage device and/or an electrical load in various applications such as in electric vehicles (EVs), power distribution systems, and renewable energy conversion systems. This is because, for example, the type of the input power source and the type of the energy storage device and/or the electrical load may be different (e.g., alternating current (AC) type or direct current (DC) type). Therefore, various power conversions are required such that the input power source, the energy storage device, and the electrical load are operationally compatible.
There are various problems associated with conventional power converter systems such as a large component count in the power converter system leading to reduced reliability, restriction on the source and load type, lack of redundancy and fault tolerance, and lack of modular and scalable power conversion. For example, in existing EVs, a dedicated power train system is required for each of the charging and discharging functionalities. Moreover, with improvements in the EVs such as all-wheel driven EVs using in-wheel motors requiring the use of multiple energy sources, the number of converters in the power train systems in the EVs increases significantly. Multiple conversions will prove to be power inefficient. In this regard, every power conversion requires hardware. For instance, in an electrically propelled car, the single or multiple motors are controlled by power electronic devices which convert a DC battery voltage into variable frequency variable voltage power supply to feed the motors. Every such a device is non-ideal and may have an efficiency in a range of about 93% to 95%. This efficiency appears to be high but when the combined efficiency is derived, it may be close to about 80% to 85%. Therefore, such a conventional arrangement/configuration involving such a high loss in the combined efficiency is undesirable.
Additionally, the increase in volume and weight of the power train systems would also lead to reduced fuel efficiencies. For example, every additional converter adds weight and space as well as requiring cooling which adds further complexity and weight to the heat management system. Furthermore, with every component that is added to the system, the reliability at the system level decreases in general.
A need therefore exists to provide a power converter system which seeks to overcome, or at least ameliorate, one or more of the deficiencies of conventional power converter systems. It is against this background that the present invention has been developed.